Humidity sensor and method for making

ABSTRACT

A humidity sensor includes a pair of opposed electrodes disposed on an insulating substrate and defining a gap therebetween and a humidity sensitive thin film covering the gap. This thin film is formed by coating a polymer of specific structure having an ethylenically unsaturated reactive group and exposing the coating to ultraviolet radiation for crosslinking. The sensor is fully water resistant and produces accurate outputs over a wide humidity range and thus can detect and determine moisture in the surrounding atmosphere.

TECHNICAL FIELD

This invention relates to a humidity sensor for detecting anddetermining moisture in the surrounding atmosphere and a method forpreparing the same.

BACKGROUND

Conventional humidity sensors are designed to detect humidity throughchanges of electrical properties, typically electric resistance. Knownsensors use electrolytes such as lithium chloride, metal oxides, andorganic polymers as the humidity sensitive material. However, thehumidity sensors using electrolytes such as lithium chloride can measureonly a narrow range of humidity and are less resistant to water in thattheir performance can be altered by dew condensation and wetting. Thehumidity sensors using metal oxides are resistant to water, but lowsensitive. Because of the lack of long-term stability when used alone,they require a heat cleaning circuit which would add to the operatingcost. The sensor structure is complex.

Among the humidity sensitive materials, organic polymers, especiallypolymeric electrolytes having a quaternary ammonium salt group have beenwidely used in commercial and industrial applications and soappreciated. For example, Japanese Patent Publication (JP-B) No.54176/1986 discloses a humidity sensitive material comprising aggregatesof latex particles formed of a copolymer between a hydrophobic monomerand an ionic or non-ionic hydrophilic monomer and having a hydrophilicsurface layer. There are exemplified some cationic compounds havingprimary to quaternary ammonium salts.

JP-B 7976/1987 discloses a humidity sensitive material in the form of apolymer which is obtained by polymerizing2-hydroxy-3-methacryloxypropyltrimethylammonium chloride to a degree ofpolymerization of 1,000 to 10,000.

JP-B 24465/1990 discloses a humidity sensitive thin film of a polymerhaving the structural formula:

    --(N.sup.+ (R.sup.1)(R.sup.2)X.sup.- --A--N.sup.+ (R.sup.3)(R.sup.4)X.sup.---B).sub.n --

wherein R¹ to R⁴ are alkyl, X⁻ is a halide ion, A and B are --(CH₂)_(m)-- wherein m≧2. The polymer may be blended with another polymer such aspolyvinyl pyrrolidone for the purposes of improving adhesion to asubstrate and water resistance. The blend is also effective in forming ahumidity sensitive thin film.

Humidity sensors using the polymeric electrolytes exemplified above asthe humidity sensitive material, however, are still low in waterresistance in that the polymeric electrolytes can be partially leachedin a high humidity region, especially in a dew condensing atmosphere.They also suffer from a hysteresis phenomenon that they producedifferent outputs at the same humidity depending on whether the humidityis increasing or decreasing. In a low humidity region having a relativehumidity (RH) of less than 10%, they have so high resistance values thatpractical humidity measurement is impossible.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a humiditysensor device having a humidity sensitive thin film which is resistantto water, maintains effective, stable performance over a long time evenin a dew condensing atmosphere, and produces accurate outputs in astable manner over a wide humidity region, even in a low humidityregion.

The present invention pertains to a humidity sensor comprising a pair ofopposed electrodes disposed on an insulating substrate and defining agap therebetween. A humidity sensitive thin film covers the gap. Thehumidity sensor may further include a water-repellent coating on saidhumidity sensitive thin film if desired. According to the feature of theinvention, the humidity sensitive thin film contains, preferablyconsists essentially of, a crosslinked product of a polymer of thefollowing general formula (1): ##STR1## wherein A and B each are adivalent group; Y₁, Y₂, Y₃, Y₄, Y₅, and Y₆ each are a monovalent group,at least one of Y₁ to Y₆ is a group terminated with an ethylenicallyunsaturated reactive group; at least two of Y₁, Y₂, Y₃, Y₄, Y₅, A, andportions thereof adjoining the nitrogen (N) atom or at least two of Y₄,Y₅, Y₆, B, and portions thereof adjoining the nitrogen (N) atom, takentogether, may form a ring with the nitrogen atom; X⁻ is a halide ion;and letter n is a number of 2 to 5,000.

Preferably the polymer has the following formula (2) or (3). ##STR2##

A and B each are a divalent group; each of R₁, R₂, R₃, and R₄ is analkyl or alkenyl group, R₁ and R₂, R₁ and A or a portion of A, R₂ and Aor a portion of A, R₃ and R₄, R₃ and A or a portion of A, R₄ and A or aportion of A, R₁ and R₃, R₁ and R₄, R₂ and R₃, or R₂ and R₄, takentogether, may form a ring with the nitrogen (N) atom; R₅ and R₆ each arean alkyl or alkenyl group; L is a divalent group; R is a hydrogen atomor alkyl group; X⁻ is a halide ion; and letter n is a number of 2 to5,000. In more preferred embodiments, the halide ion represented by X⁻is a chloride ion, the divalent group represented by A is an alkylene,alkenylene or arylene group or a mixture thereof, and the divalent grouprepresented by B is an alkylene, alkenylene or arylene group in which atleast one of an oxy group (--O--) and a carbonyl group (--CO--) mayintervene or a mixture thereof.

In general, the humidity sensor is prepared by coating an aqueoussolution of the polymer, and exposing the polymer to ultravioletradiation for crosslinking, thereby forming a humidity sensitive thinfilm. More preferably, the polymer is obtained by reacting a diaminecompound with a dihalogen compound to form an intermediate polymer andintroducing an ethylenically unsaturated reactive group into theintermediate polymer at each end; and the polymer is exposed toradiation, obtaining the crosslinked product.

ADVANTAGES

According to the present invention, a humidity sensitive thin film of aconductive polymer is provided so as to cover a pair of opposedelectrodes on an insulating substrate. The humidity sensitive thin filmcontains a crosslinked product of a polymer of formula (1), preferablyformula (2) or (3). The humidity sensitive thin film is formed bycoating an aqueous solution of the polymer and crosslinking the polymer,preferably by exposure to ultraviolet radiation. As shown by formulae(1) to (3), the polymer is structurally characterized by containing aquaternary ammonium salt group (including a cyclized one) in itsbackbone and having an ethylenically unsaturated reactive group at oneor both, preferably both of the terminal ends of the polymer.

In the humidity sensitive thin film containing the specific polymer, thequaternary ammonium salt group moiety of the polymer moleculecontributes to electric conductivity and the counter ion thereto isdissociated with moisture in the surrounding atmosphere to develop ionicconduction. Humidity is detected by utilizing the phenomenon that thedegree of dissociation varies as the moisture content in the atmosphereincreases or decreases.

Since the polymer contains a quaternary ammonium salt group in itsbackbone, the humidity sensor produces accurate outputs withouthysteresis.

In the preferred embodiment wherein the counter ion to the quaternaryammonium salt group in the polymer is a chloride ion, a low humidityregion of RH 0% to 10% can be measured, substantially spreading themeasurable humidity region. The humidity sensor device of the inventioncan measure humidity over an entire range from RH 0% to RH 100%, whichwas unmeasurable with conventional sensors.

Since the polymer has an ethylenically unsaturated reactive group as aterminal group, it is crosslinkable upon exposure to radiation,typically ultraviolet radiation. Crosslinking ensures water resistancefor the humidity sensitive thin film at no sacrifice of humiditysensitivity. There is thus obtained a humidity sensor device havingimproved water resistance as well as humidity sensitivity.

JP-B 24465/1990 cited above discloses a polymer containing a quaternaryammonium group in its backbone, which is similar to the polymeraccording to the present invention. Unlike the present invention, astructure having an ethylenically unsaturated reactive group introducedat the polymer end is referred to nowhere. In this respect, the presentinvention is clearly different from the patent publication. Although thecombined use of another polymer such as polyvinyl pyrrolidone for thepurpose of improving water resistance is recommended in the patentpublication, the water resistance is apparently inferior to that of thesensor according to the present invention as will be demonstrated laterin Examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill be better understood by reading the following description taken inconjunction with the accompanying drawings.

FIG. 1 is a plan view of a humidity sensor according to one embodimentof the invention.

FIG. 2 is a graph showing the output voltage versus relative humidity ofthe humidity sensor of Example 1.

FIG. 3 is a graph showing the water resistance of the humidity sensor ofExample 1.

FIGS. 4 and 5 are graphs showing the output and water resistance of thesensor of Example 2, respectively.

FIGS. 6 and 7 are graphs showing the output and water resistance of thesensor of Example 3, respectively.

FIGS. 8 and 9 are graphs showing the output and water resistance of thesensor of Example 4, respectively.

FIGS. 10 and 11 are graphs showing the output and water resistance ofthe sensor of Example 5, respectively.

FIGS. 12 and 13 are graphs showing the output and water resistance ofthe sensor of Example 6, respectively.

FIGS. 14 and 15 are graphs showing the output and water resistance ofthe sensor of Example 7, respectively.

FIGS. 16 and 17 are graphs showing the output and water resistance ofthe sensor of Example 8, respectively.

FIGS. 18 and 19 are graphs showing the output and water resistance ofthe sensor of Example 9, respectively.

FIGS. 20 and 21 are graphs showing the output and water resistance ofthe sensor of Example 10, respectively.

FIGS. 22 and 23 are graphs showing the output and water resistance ofthe sensor of Example 12, respectively.

FIGS. 24-32 are graphs showing the water resistance of the humiditysensors of Examples 13-21, respectively.

FIGS. 33 and 34 are graphs showing the output and water resistance ofthe sensor of Example 22, respectively.

FIGS. 35 and 36 are graphs showing the output and water resistance ofthe sensor of Example 23, respectively.

FIGS. 37 and 38 are graphs showing the output and water resistance ofthe sensor of Example 24, respectively.

FIGS. 39 and 40 are graphs showing the output and water resistance ofthe sensor of Example 25, respectively.

FIGS. 41 and 42 are graphs showing the output and water resistance ofthe sensor of Example 26, respectively.

FIGS. 43 and 44 are graphs showing the output and water resistance ofthe sensor of Example 27, respectively.

FIGS. 45 and 46 are graphs showing the output and water resistance ofthe sensor of Example 28, respectively.

FIGS. 47 and 48 are graphs showing the output and water resistance ofthe sensor of Example 29, respectively.

FIG. 49 is a graph showing the water resistance of the humidity sensorof Example 30.

FIGS. 50 and 51 are graphs showing the output and water resistance ofthe sensor of Example 31, respectively.

FIGS. 52 and 53 are graphs showing the output and water resistance ofthe sensor of Example 32, respectively.

FIGS. 54 and 55 are graphs showing the output and water resistance ofthe sensor of Example 33, respectively.

FIGS. 56 and 57 are graphs showing the output and water resistance ofthe sensor of Example 34, respectively.

FIG. 58 is a graph showing the water resistance of the humidity sensorof Example 35.

FIGS. 59 and 60 are graphs showing the output and water resistance ofthe sensor of Example 36, respectively.

FIG. 61 is a graph showing the water resistance of the humidity sensorof Example 37.

FIGS. 62 and 63 are graphs showing the output and water resistance ofthe sensor of Example 38, respectively.

FIGS. 64 and 65 are graphs showing the output and water resistance ofthe sensor of Example 39, respectively.

FIGS. 66-106 are graphs showing the water resistance of the humiditysensors of Examples 40-80, respectively.

FIG. 107 is a graph showing the output of the humidity sensor ofComparative Example 1.

FIGS. 108 and 109 are graphs showing the output and water resistance ofthe sensor of Comparative Example 2, respectively.

FIGS. 110 and 111 are graphs showing the output and water resistance ofthe sensor of Comparative Example 3, respectively.

BEST MODE FOR CARRYING OUT THE INVENTION

According to the present invention, a humidity sensor is defined ascomprising a pair of opposed electrodes disposed on an insulatingsubstrate and defining a gap therebetween and a humidity sensitive thinfilm disposed on the gap. The humidity sensitive thin film contains acrosslinked product of a polymer of the following general formula (1).##STR3##

In formula (1), A, B, X⁻ and n are as defined above and will bedescribed later in conjunction with formulae (2) and (3).

Each of Y₁ to Y₆ is a monovalent group. At least one of Y₁ to Y₆ is agroup terminated with an ethylenically unsaturated reactive group.Exemplary groups are acryloyloxy, methacryloyloxy, acryloylimino,methacryloylimino, vinyl, allyl, diallylmethyl, allyloxy,diacryloylimino, and dimethacryloylimino groups. The other monovalentgroups represented by Y₁ to Y₆ include alkyl groups, alkenyl groups andhalogen atoms. Examples of the alkyl and alkenyl groups are the same asR₁ and analogs in formulae (2) and (3), which will be described later.Examples of the halogen atom include chlorine, bromine and iodine. Anytwo or more of Y₁ to Y₅, A, and portions thereof adjoining the nitrogen(N) atom, taken together, may form a ring with the nitrogen atom.Alternatively, any two or more of Y₄ to Y₆, B, and portions thereofadjoining the nitrogen (N) atom, taken together, may form a ring withthe nitrogen atom. The ring thus formed is the same as the ring formedby R₁ and analogs in formulae (2) and (3), which will be describedlater.

The polymer of formula (1) should have at least one, preferably abouttwo ethylenically unsaturated reactive groups. No upper limit is imposedon the number of such reactive groups although it is preferred that thepolymer contains double bonds in an amount of 1×10⁻³ to 2 meq/g,especially 2×10⁻³ to 1 meq/g calculated as a double bond equivalent perpolymer weight.

The monovalent groups represented by Y₂ to Y₅ may contain a linkagebetween recurring units in the molecular structure of formula (1) whilethe recurring units in formula (1) may be identical or different.

Preferably the polymer of formula (1) contains quaternary ammonium saltgroups in an amount of 1.2 to 9.5 meq/g, especially 1.5 to 9.5 meq/gcalculated as a cation equivalent per polymer weight.

Preferred among the polymers of formula (1) are polymers of formulae (2)and (3). ##STR4##

In formulae (2) and (3) as well as in formula (1), each of A and B is adivalent group.

The divalent group represented by A is preferably an alkylene,alkenylene or arylene group or a mixture thereof. These groups may havesubstituents, for example, hydroxyl groups, alkyl groups such as methyl,and carbamoyl groups. The alkylene groups preferably have 1 to 20 carbonatoms in total and if substituted, they preferably have 1 to 5 hydroxylgroups. The alkenylene groups preferably have 2 to 10 carbon atoms intotal. The arylene groups preferably have 6 to 20 carbon atoms in total.When the divalent group represented by A is a mixture of these groups,the mixture preferably has 3 to 20 carbon atoms in total.

Illustrative, preferred examples of A include

--(CH₂)_(m) -- wherein m is an integer of 1 to 20,

--CH₂ CH═CH--CH₂ --,

--CH₂ --CH(OH)--CH₂ --CH(CH₃)--CH₂ --CH₂ --,

--C₆ H₄ --C₆ H₄ --, and

--C₆ H₄ --CH(OH)--C₆ H₄ --.

The divalent group represented by B is preferably an alkylene,alkenylene or arylene group in which an oxy group (--O--) and/or acarbonyl group (--CO--) may intervene or a mixture thereof. Morepreferably, the divalent group represented by B is an alkylene group, analkylene group having an intervening oxy (--O--) and/or carbonyl(--CO--) group, an alkenylene group, an arylene group, or a mixturethereof. These groups may have substituents, for example, hydroxylgroups and alkenyl groups such as vinyl. The alkylene groups preferablyhave 1 to 20 carbon atoms in total and if substituted, they preferablyhave 1 to 5 hydroxyl groups. If --O-- or --CO-- intervenes in thealkylene group, the number of the intervening groups is preferably 1 to5. The alkenylene groups preferably have 2 to 10 carbon atoms in total.The arylene groups preferably have 6 to 20 carbon atoms in total. Whenthe divalent group represented by B is a mixture of these groups, themixture preferably has 3 to 20 carbon atoms in total.

Illustrative, preferred examples of B include

--(CH₂)_(m) -- wherein m is an integer of 1 to 20,

(CH₂)₂ --CH(OH)--CH₂ --,

--CH₂ --CH(OH)--CH₂ --,

--CH₂ --CH═CH--CH₂ --,

--CH₂ --CH(CH═CH₂)--,

--(CH₂ --CH₂ --O)₂ --(CH₂)--,

--CH₂ --(CO)--CH₂ --, and

CH₂ --C₆ H₄ --CH₂ --.

Each of R₁, R₂, R₃, and R₄ is an alkyl or alkenyl group. The alkylgroups represented by R₁ to R₄ preferably have 1 to 10 carbon atoms.They may be substituted ones although unsubstituted groups arepreferred. Exemplary alkyl groups are methyl, ethyl, propyl and butylgroups.

The alkenyl groups represented by R₁ to R₄ preferably have 1 to 10carbon atoms. They may be substituted ones although unsubstituted groupsare preferred. Exemplary alkenyl groups are vinyl, allyl, propenyl andbutenyl groups.

R₁ and R₂, R₁ and A or a portion of A, R₂ and A or a portion of A, R₃and R₄, R₃ and A or a portion of A, R₄ and A or a portion of A, R₁ andR₃, R₁ and R₄, R₂ and R₃, or R₂ and R₄, taken together, may form a ringwith the nitrogen (N) atom. The ring is preferably a five orsix-membered, especially six-membered nitrogenous heterocyclic ring. Thering may also be a bridging ring. Preferred examples of the nitrogenousheterocyclic ring include pyridine, 1,4-diazabicyclo [2.2.2] octane,piperidine, piperazine, and pyrazine rings which may have carbamoyl orother substituents if desired.

Each of R₅ and R₆ in formula (2) is an alkyl or alkenyl group. Preferredis an alkyl group, especially having 1 to 10 carbon atoms. It may have asubstituent although unsubstituted alkyl groups are preferred. Forexample, methyl and ethyl group are most preferred for R₅ and R₆.Examples of the alkenyl group represented by R₅ and R₆ are the same asdescribed for R₁ to R₄.

In formulae (2) and (3), L is a divalent group. Preferred examples of Lin formula (2) include --COO(CH₂)₂ --, --CONH(CH₂)₃ --, and --(CH₂)_(m)-- wherein m is an integer of 1 to 20. Preferred examples of L informula (3) include --OCH₂ CH₂ --, --(CH₂)_(m) -- wherein m is aninteger of 1 to 20, --COO (CH₂)₂ --, --COOCH₂ CH(OH)CH₂ --, and --CH₂--C₆ H₄ -- (para- or meta--).

Alternatively, two or three of R₅, R₆ and L, taken together, may form apyridine or another ring with the nitrogen (N) atom.

In formulae (2) and (3), R is a hydrogen atom or alkyl group, with thehydrogen atom and methyl being preferred.

In formulae (2) and (3), X⁻ is a halide ion, for example, chloride,bromide and iodide ions. The chloride and bromide ions are preferred,with the chloride ion being most preferred. The ions represented by X⁻are often identical although they may be different.

Letter n is a number of 2 to 5,000.

The polymers of formulae (1) to (3) generally have a number averagemolecular weight Fin of about 1,000 to about 1,000,000.

The preferred polymers of formulae (2) and (3) are prepared as follows.

The polymer of formula (2) is synthesized according to the followingreaction scheme I. ##STR5##

First, a diamine compound is reacted with a dihalogen compound to forman intermediate polymer I having a quaternary ammonium salt group andterminated with a halogen atom. In this regard, the reactants arereacted under conditions that the molar ratio of dihalogen compound todiamine compound is 1.1 to 2.0. To assure that the intermediate polymerI is terminated with a halogen atom, the dihalogen compounds may beadded in two divided portions wherein it is first added in an amount of1 to 1.3 mol per mole of the diamine compound and the remainder issubsequently added. Reaction is effected in a non-aqueous solvent suchas methanol, isopropanol, methoxyethanol and 2-ethoxyethanol at a refluxtemperature or a temperature of about 100° C. for about 5 to 100 hours.

Next, intermediate polymer I is reacted with a compound A having anethylenically unsaturated reactive group to introduce an ethylenicallyunsaturated reactive group at each end of intermediate polymer I,obtaining a polymer of formula (2). This reaction may be carried outsubsequent to the first reaction. That is, the compound A having anethylenically unsaturated reactive group is added to the reactionsolution in an approximately equimolar amount to the dihalogen compound.Reaction is effected at a temperature of about 15° to 100° C. in thepresence of a polymerization inhibitor (e.g., m-dinitrobenzene) forabout 10 to 150 hours. If this reaction is effected under conditionsthat at least some of the ethylenically unsaturated reactivegroups-being introduced will undergo polymerization, then the resultingpolymer is more resistant to water when used as a humidity sensitivethin film. To this end, reaction is preferably effected at 70° C. orhigher, especially 70° to 100° C. Thereafter, the reaction solution wasadded dropwise to a suitable solvent such as acetone and ethyl acetatewhereupon the reaction product will precipitate. The precipitate iscollected by filtration and purified, recovering the end product.

The polymer of formula (3) is synthesized according to the followingreaction scheme II. ##STR6##

First, a diamine compound is reacted with a dihalogen compound to forman intermediate polymer II having a quaternary ammonium salt group andterminated with an amino group. In this regard, the reactants arereacted under conditions that the molar ratio of diamine compound todihalogen compound is 1.1 to 2.0. The remaining conditions are the sameas in the reaction to form intermediate polymer I. The conditions toassure that the intermediate polymer II is terminated with an aminogroup are analogous to those for intermediate polymer I.

Next, intermediate polymer II is reacted with a compound B having anethylenically unsaturated reactive group to introduce an ethylenicallyunsaturated reactive group at each end of intermediate polymer II,obtaining a polymer of formula (3). This reaction may be carried out inthe same manner as in the polymer of formula (2). This is also true forthe reaction conditions under which at least some of the ethylenicallyunsaturated reactive groups being introduced will undergopolymerization.

As mentioned above, the polymers of formulae (2) and (3) are preparedthrough reaction between a diamine and a dihalide. Any desired ones ofdiamines and dihalides may be used as long as they can react inaccordance with the above-illustrated schemes. It is understood thatthese intermediate polymers and final polymers are generally obtained asa mixture of oligomers having a degree of polymerization (n) of about 2to 20 and polymers having a degree of polymerization (n) in excess of20.

Preferred examples of the diamine compound used herein are given below.##STR7##

Preferred examples of the dihalogen compound used herein are givenbelow. ##STR8##

In these examples, X is as defined previously, with chlorine and bromineatoms being preferred.

Examples of the intermediate polymers I and II to the polymers offormulae (2) and (3) are shown below as polymers resulting fromcombinations of the diamine and dihalogen compounds illustrated justabove. Note that numerical values in the parentheses represent a molarratio.

(1) Polymer resulting from a combination of A-16/B-10 (50/50)

(2) Polymer resulting from a combination of A-8/B-12/B10 (50/48/2)

(3) Polymer resulting from a combination of A-8/B-13/B-10 (50/48/2)

(4) Polymer resulting from a combination of A-8/B-15/B-10 (50/48/2)

(5) Polymer resulting from a combination of A-16/B-2 (50/50)

(6) Polymer resulting from a combination of A-7/B-10 (50/50)

(7) Polymer resulting from a combination of A-2/B-10 (50/50)

(8) Polymer resulting from a combination of A-9/B-10 (50/50)

(9) Polymer resulting from a combination of A-16/B-9 (50/50)

(10) Polymer resulting from a combination of A-3/A-8/B-10 (2/48/50)

(11) Polymer resulting from a combination of A-14/A-16/B-17 (49/1/50)

(12) Polymer resulting from a combination of A-11/B-16 (50/50)

(13) Polymer resulting from a combination of A-6/B-4/B-15 (50/47/3)

(14) Polymer resulting from a combination of A-11/B-6 (50/50)

(15) Polymer resulting from a combination of A-13/B-3 (50/50)

(16) Polymer resulting from a combination of A-10/B-15 (50/50)

(17) Polymer resulting from a combination of A-15/B-16 (50/50)

(18) Polymer resulting from a combination of A-4/B-10 (50/50)

(19) Polymer resulting from a combination of A-10/B-12/B-10 (50/48/2)

(20) Polymer resulting from a combination of A-8/B-2 (50/50)

(21) Polymer resulting from a combination of A-7/A-16/B-10 (15/35/50)

(22) Polymer resulting from a combination of A-8/A-16/B-10 (15/35/50)

(23) Polymer resulting from a combination of A-9/A-16/B-10 (15/35/50)

(24) Polymer resulting from a combination of A-10/A-16/B-10 (15/35/50)

(25) Polymer resulting from a combination of A-8/B-13 (50/50)

(26) Polymer resulting from a combination of A-8/A-10/B-13 (35/15/50)

(27) Polymer resulting from a combination of A-8/B-13/B-10 (50/40/10)

(28) Polymer resulting from a combination of A-8/B-13/B-2 (50/40/10)

(29) Polymer resulting from a combination of A-9/B-13 (50/50)

(30) Polymer resulting from a combination of A-8/A-9/B-13 (25/25/50)

(31) Polymer resulting from a combination of A-9/A-10/B-13 (25/25/50)

The compounds A and B used in introducing an ethylenically unsaturatedreactive group into intermediate polymers I and II at both ends are notcritical as long as they have an ethylenically unsaturated reactivegroup such as an acryloyloxy, methacryloyloxy, acryloylimino,methacryloylimino, vinyl, allyl, diallylmethyl, allyloxy,diacryloylimino, and dimethacryloylimino group. Where intermediatepolymers I and II as produced already have an ethylenically unsaturatedreactive group as in the case of, for example, polymers (10), (11) and(13), they may be used as the (final) polymer in the practice of theinvention without further reaction.

Preferred examples of compound A used in combination with intermediatepolymer I are given below as E-1 to E-7. ##STR9##

Preferred examples of compound B used in combination with intermediatepolymer II are given below as F-1 to F-6. ##STR10##

In the formulae of E-1 to E-7 and F-1 to F-6, Me is methyl, Et is ethyl,and X is halogen as defined above.

In the practice of the invention, the polymers of formula (1),preferably formulae (2) and (3) are generally used alone although amixture of two or more polymers may be used.

The humidity sensitive thin film used herein contains a crosslinkedproduct of a polymer of formula (1), preferably formula (2) or (3) aspreviously described. The thin film is preferably formed by thefollowing procedure. First a coating solution containing a polymer offormula (1), preferably formula (2) or (3) is prepared. The preferredcoating solution is an aqueous solution containing 1 to 10% by weight ofthe polymer. At this point, a polymerization initiator, for example,0.03 to 0.7% by weight of a water-soluble benzophenone is preferablyadded to the solution so that the resulting coating is ready forcrosslinking by subsequent exposure to radiation, typically ultravioletradiation. The coating solution is applied to an insulating substratehaving electrodes formed thereon to thereby form a humidity sensitivethin film. For the coating purpose, well-known techniques such asdipping, brush coating, gravure coating, screen printing, and spincoating techniques are useful. Any desired one of these coatingtechniques may be chosen depending on the overall procedure and the typeand application of a final product.

After the coating is formed in this way, it is dried at a temperature ofabout 15° to 100° C. for about 3 to 15 minutes. Thereafter the coatingor polymer is crosslinked, preferably by exposure to radiation,especially ultraviolet radiation. Crosslinking by exposure toultraviolet radiation may be carried out by any well-known technique.Often ultraviolet radiation having an intensity of at least about 50mW/cm² is irradiated in a dose of about 200 to 2,500 mJ/cm².Conventional light sources such as mercury lamps may be used as theultraviolet source.

The humidity sensitive thin film as crosslinked preferably has athickness of about 0.5 to 10 μm, especially about 0.5 to 7 μm. Outsidethis range, a thicker film would be slow in response of its electricresistance to humidity whereas a thinner film would produce loweroutputs in the low humidity region and be less resistant to water.

In the practice of the invention, a water-repellent coating may beformed on the humidity sensitive thin film in order to prevent anyinfluence of water droplets adhering to the sensor for thereby insuringquick accurate humidity measurement. The water-repellent coatingpreferably has a contact angle with water of at least 90° , especially90° to 130° and a sufficient thickness to allow for moisturepenetration, typically up to 5 μm, especially 0.1 to 2 μm.

The material of which the water-repellent coating is constructedincludes hydrophobic polymers, for example, fluorinated polymers such aspolytetrafluoroethylene, olefinic polymers such as polyethylene andpolypropylene, and silicone polymers. The water-repellent coating may beformed by any desired technique, typically by dissolving the material ina suitable solvent such as saturated carbon fluoride and coating thesolution.

As long as the humidity sensor device of the invention includes theabove-mentioned humidity sensitive thin film on an insulating substratehaving electrodes formed thereon, the remaining construction is notcritical.

Referring to FIG. 1, there is illustrated in plan view one exemplaryarrangement of the humidity sensor device.

The humidity sensor 1 includes a pair of comb-shaped electrodes 4 on aninsulating substrate 2. The pair of comb-shaped electrodes 4 aredisposed on the substrate 2 and interdigitated with each other to definea gap 5 of a certain distance therebetween. The gap typically has adistance of about 100 to 500 μm. A humidity sensitive thin film 3 isformed over the insulating substrate 2 and comb-shaped electrodes 4. Thecomb-shaped electrodes 4 are provided at one end with electrode tabs 6to which leads 7 are connected with solder welds 8. A resist film 9 isformed for preventing diffusion of the electrode material. In detectinghumidity in the surrounding atmosphere, voltage, preferably AC voltageis applied across the electrodes 4. Since the humidity sensitive thinfilm 3 has changed its electrical resistance in accordance with thehumidity, the output voltage changes therewith, in terms of which thehumidity is detectable. The applied voltage is typically up to about 12volts.

The insulating substrate 2 used herein may be formed of any desiredmaterial which is electrically insulating and well receptive to thehumidity sensitive thin film 3. Useful substrates are glass, plastics,ceramics and metals coated with insulating material.

The electrodes 4 may be made of any conventional electrode material. Forexample, they are formed by screen printing low resistance pastecontaining Au or RuO₂ and optionally glass frit, followed by hightemperature firing. The electrode tabs 6 may be made of any conventionalmaterial which is compatible with the solder 8. For example, Ag--Pdalloy is printed in a conventional manner and baked at high temperaturesto form the electrode tabs 6. Where gold is used as the electrodes 4, itis preferred that the resist film 9 of resist or glass is furtherprovided in order to prevent diffusion of Au during soldering. No limitsare imposed on the thickness and configuration of the resist film 9 aslong as it is effective for preventing diffusion of Au during soldering.

The humidity sensor of the present invention is not limited to theillustrated embodiment. Any desired shape or arrangement may beemployed.

EXAMPLE

Examples of the present invention are given below by way of illustrationand not by way of limitation.

Example 1

According to reaction scheme I, 8.6 g (0.05 mol) ofN,N,N',N'-tetramethyl-1,6-diaminohexane and 6.8 g (0.06 mol) of1,3-dichloropropane were dissolved in 7.5 g of methanol and stirred for25 hours at the reflux temperature, effecting quaternization reaction toform an intermediate polymer as shown in reaction formula (1) below.Then 10.2 g (0.06 mol) of N-(3-dimethylaminopropyl)methacrylamide and0.2 g of m-dinitrobenzene as a polymerization inhibitor were added tothe reaction solution. The solution was stirred at 35° C. for 100 hours,introducing a reactive group into the intermediate polymer at its end asshown in reaction formula (2) below. ##STR11##

The reaction solution was added dropwise to a large volume of acetonewhereupon the polymer precipitated. The precipitate was collected byfiltration and then dried in vacuum. After precipitation andpurification of the polymer in this way, an aqueous solution containing5% by weight of the polymer was prepared. To the solution 0.2% by weightof KAYACURE ABQ (commercially available from Nippon Kayaku K.K.) wasadded as a polymerization initiator to complete a coating solution. Notethat the polymer had Fin of about 110,000 prior to crosslinking.

A humidity sensor 1 as shown in FIG. 1 was fabricated. A porous ceramicsubstrate of alumina was used as the insulating substrate 2. Comb-shapedelectrodes were formed on the substrate by screen printing pastecontaining RuO₂ and glass frit and firing at high temperature. Theinterdigitated electrodes defined a gap of about 225 μm widetherebetween. The coating solution was coated onto the insulatingsubstrate 2 by dipping and then dried at 100° C. for 5 minutes, forminga polymer coating. In a nitrogen atmosphere, the coatings on theelectrode-bearing surface and the rear surface of the substrate wereexposed to ultraviolet radiation for one minute on each surface, causingthe polymer to crosslink. The dose of ultraviolet radiation was 1,000mJ/cm². The resulting humidity sensitive thin film 3 had a thickness of5 μm.

The humidity sensor thus fabricated was evaluated for output andexamined by a water resistance test.

For evaluating the output, a divided flow humidity generating machinemodel SRH-1 (manufactured by Shinei K.K.) was used. The humidity sensorwas incorporated in the circuit described and shown in JP-A 123843/1990.The humidity sensor incorporated in the circuit was set in the humiditygenerating machine where the relative humidity was changed stepwise froma low level to a high level and then from the high level to the lowlevel both at 25° C. During the humidity cycling process, the humiditysensor which was allowed to stand at a selected relative humidity for 10minutes was measured for output voltage. The selected relative humiditylevels were RH 0%, RH 10%, RH 20%, RH 30%, RH 50%, RH 70%, and RH 90%.The results are plotted in FIG. 2.

In the water resistance test, the humidity sensor having undergonehumidity cycling for output voltage monitoring as mentioned above wasimmersed in distilled water for 1 minute, dried in air, and measured foroutput voltage again, which was compared with the initial output voltage(prior to water immersion). The time duration when the humidity sensorwas immersed in distilled water was prolonged to 10 minutes, 30 minutesand 60 minutes whereupon the output voltage was similarly measured. Theresults are plotted in FIG. 3.

It is evident from FIG. 2 that the inventive humidity sensor exhibits nohysteresis and is able to measure low humidity, especially in a regionof RH 10% or lower. It is evident from FIG. 3 that the inventivehumidity sensor is fully resistant to water. The advantages of thepresent invention are thus demonstrated.

Example 2

8.6 g (0.05 mol) of N,N,N',N'-tetramethyl-1,6-diaminohexane and 7.7 g(0.06 mol) of 1,3-dichloro-2-propanol were dissolved in 8.1 g ofisopropanol and stirred for 50 hours at the reflux temperature,effecting quaternization reaction to form an intermediate polymer. Then10.2 g (0.06 mol) of N-(3-dimethylaminopropyl)methacrylamide and 0.2 gof m-dinitrobenzene as a polymerization inhibitor were added to thereaction solution. The solution was stirred at 45° C. for 120 hours,introducing a reactive group into the intermediate polymer at its end.The resulting polymer was precipitated and purified. Except that thispolymer was used as a conductive component, a humidity sensor wasfabricated as in Example 1 by preparing an aqueous solution of thepolymer and coating it to form a humidity sensitive thin film. Note thatthe polymer had Fin of about 110,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 4 shows plots of output voltageversus relative humidity and FIG. 5 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 4 and 5.

Example 3

5.6 g (0.05 mol) of 1,4-diazabicyclo[2.2.2] octane and 7.1 g (0.05 mol)of 1,5-dichloropentane were dissolved in 6.4 g of 2-ethoxyethanol andstirred for 60 hours at the reflux temperature, effecting quaternizationreaction. The reaction solution was added dropwise to a large volume ofacetone whereupon the product was precipitated and purified. The productand 2.3 g (0.02 mol) of 1,3-dichloropropane were dissolved in 6.4 g of2-ethoxyethanol. The reaction solution was stirred for 20 hours at thereflux temperature, effecting quaternization reaction again to form anintermediate polymer. Then 10.2 g (0.06 mol) ofN-(3-dimethylaminopropyl)methacrylamide and 0.2 g of m-dinitrobenzene asa polymerization inhibitor were added to the reaction solution. Thesolution was stirred at 45° C. for 120 hours, introducing a reactivegroup into the intermediate polymer at its end. The resulting polymerwas precipitated and purified. Except that this polymer was used as aconductive component, a humidity sensor was fabricated as in Example 1by preparing an aqueous solution of the polymer and coating it to form ahumidity sensitive thin film. Note that the polymer had Mn of about90,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 6 shows plots of output voltageversus relative humidity and FIG. 7 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 6 and 7.

Example 4

9.9 g (0.05 mol) of 1,3-di(4-pyridyl)propane and 6.8 g (0.06 mol) of1,3-dichloropropane were dissolved in 8.8 g of 2-ethoxyethanol andstirred for 75 hours at the reflux temperature, effecting quaternizationreaction to form an intermediate polymer. Then 10.2 g (0.06 mol) ofN-(3-dimethylaminopropyl)methacrylamide and 0.2 g of m-dinitrobenzene asa polymerization inhibitor were added to the reaction solution. Thesolution was stirred at 45° C. for 120 hours, introducing a reactivegroup into the intermediate polymer at its end. The resulting polymerwas precipitated and purified. Except that this polymer was used as aconductive component, a humidity sensor was fabricated as in Example 1by preparing an aqueous solution of the polymer and coating it to form ahumidity sensitive thin film. Note that the polymer had Mn of about80,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 8 shows plots output voltageversus relative humidity and FIG. 9 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 8 and 9.

Example 5

9.3 g (0.05 mol) of N,N,N',N'-tetraethyl-1,3-diaminopropane and 6.8 g(0.06 mol) of 1,3-dichloropropane were dissolved in 8.5 g of2-ethoxyethanol and stirred for 60 hours at the reflux temperature,effecting quaternization reaction to form an intermediate polymer. Then10.2 g (0.06 mol) of N-(3-dimethylaminopropyl)methacrylamide and 0.2 gof m-dinitrobenzene as a polymerization inhibitor were added to thereaction solution. The solution was stirred at 45° C. for 120 hours,introducing a reactive group into the intermediate polymer at its end.The resulting polymer was precipitated and purified. Except that thispolymer was used as a conductive component, a humidity sensor wasfabricated as in Example 1 by preparing an aqueous solution of thepolymer and coating it to form a humidity sensitive thin film. Note thatthe polymer had Mn of about 80,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 10 shows plots of output voltageversus relative humidity and FIG. 11 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 10 and 11.

Example 6

5.7 g (0.05 mol) of N,N'-dimethylpiperazine and 6.8 g (0.06 mol) of1,3-dichloropropane were dissolved in 6.7 g of 2-ethoxyethanol andstirred for 60 hours at the reflux temperature, effecting quaternizationreaction to form an intermediate polymer. Then 10.2 g (0.06 mol) ofN-(3-dimethylaminopropyl)methacrylamide and 0.2 g of m-dinitrobenzene asa polymerization inhibitor were added to the reaction solution. Thesolution was stirred at 45° C. for 120 hours, introducing a reactivegroup into the intermediate polymer at its end. The resulting polymerwas precipitated and purified. Except that this polymer was used as aconductive component, a humidity sensor was fabricated as in Example 1by preparing an aqueous solution of the polymer and coating it to form ahumidity sensitive thin film. Note that the polymer had Fin of about100,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 12 shows plots of output voltageversus relative humidity and FIG. 13 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 12 and 13.

Example 7

8.6 g (0.05 mol) of N,N,N',N'-tetramethyl-1,6-diaminohexane and 10.5 g(0.06 mol) of α,α'-dichloro-p-xylene were dissolved in 9.6 g of2-ethoxyethanol and stirred for 70 hours at the reflux temperature,effecting quaternization reaction to form an intermediate polymer. Then10.2 g (0.06 mol) of N-(3-dimethylaminopropyl)methacrylamide and 0.2 gof m-dinitrobenzene as a polymerization inhibitor were added to thereaction solution. The solution was stirred at 45° C. for 120 hours,introducing a reactive group into the intermediate polymer at its end.The resulting polymer was precipitated and purified. Except that thispolymer was used as a conductive component, a humidity sensor wasfabricated as in Example 1 by preparing an aqueous solution of thepolymer and coating it to form a humidity sensitive thin film. Note thatthe polymer had Fin of about 80,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 14 shows plots of output voltageversus relative humidity and FIG. 15 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 14 and 15.

Example 8

0.36 g (0.0025 mol) of N,N,N',N'-tetramethyl-2-butene-1,4-diaminobutane,5.3 g (0.048 mol) of 1,4-diazabicyclo[2.2.2]octane, and 5.7 g (0.05 mol)of 1,3-dichloropropane were dissolved in 7.4 g of ethanol and stirredfor 70 hours at the reflux temperature, effecting quaternizationreaction. The resulting polymer was precipitated and purified. Exceptthat this polymer was used as a conductive component, a humidity sensorwas fabricated as in Example 1 by preparing an aqueous solution of thepolymer and coating it to form a humidity sensitive thin film. Note thatthe polymer had Mn of about 80,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 16 shows plots of output voltageversus relative humidity and FIG. 17 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 16 and 17.

Example 9

8.6 g (0.05 mol) of N,N,N',N'-tetramethyl-1,6-diaminohexane and 12.1 g(0.06 mol) of 1,3-dibromopropane were dissolved in 10.9 g of methanoland stirred for 10 hours at the reflux temperature, effectingquaternization reaction to form an intermediate polymer. Then 9.36 g(0.06 mol) of N-(3-dimethylaminopropyl)acrylamide and 0.4 g ofm-dinitrobenzene as a polymerization inhibitor were added to thereaction solution. The solution was stirred at 35° C. for 100 hours,introducing a reactive group into the intermediate polymer at its end.The resulting polymer was precipitated and purified. Except that thispolymer was used as a conductive component, a humidity sensor wasfabricated as in Example 1 by preparing an aqueous solution of thepolymer and coating it to form a humidity sensitive thin film. Note thatthe polymer had Mn of about 150,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 18 shows plots of output voltageversus relative humidity and FIG. 19 shows the results of the waterresistance test. It is seen from FIG. 18 that this sensor enabledhumidity measurement over a relatively wide region although measurementwas impossible in the region of RH 0% through 10% because the dibromocompound was used as the dihalogen compound. The sensor had improvedwater resistance as seen from FIG. 19.

Example 10

5.6 g (0.05 mol) of 1,4-diazabicyclo[2.2.2]octane and 13.1 g (0.06 mol)of 1,3-dibromo-2-propanol were dissolved in 9.4 g of 2-ethoxyethanol andstirred for 30 hours at the reflux temperature, effecting quaternizationreaction to form an intermediate polymer. Then 10.2 g (0.06 mol) ofN-(3-dimethylaminopropyl)methacrylamide and 0.4 g of m-dinitrobenzene asa polymerization inhibitor were added to the reaction solution. Thesolution was stirred at 35° C. for 100 hours, introducing a reactivegroup into the intermediate polymer at its end. The resulting polymerwas precipitated and purified. Except that this polymer was used as aconductive component, a humidity sensor was fabricated as in Example 1by preparing an aqueous solution of the polymer and coating it to form ahumidity sensitive thin film. Note that the polymer had Mn of about130,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 20 shows plots of output voltageversus relative humidity and FIG. 21 shows the results of the waterresistance test. FIGS. 20 and 21 show that the results are the same asin Example 9.

Example 11

According to reaction scheme II, 10.3 g (0.06 mol) ofN,N,N',N'-tetramethyl-1,6-diaminohexane and 5.7 g (0.05 mol) of1,3-dichloropropane were dissolved in 8.0 g of methanol and stirred for25 hours at the reflux temperature, effecting quaternization reaction toform an intermediate polymer as shown in reaction formula (3) below.Then 6.4 g (0.06 mol) of 2-chloroethyl vinyl ether and 0.2 g ofm-dinitrobenzene as a polymerization inhibitor were added to thereaction solution. The solution was stirred at 35° C. for 100 hours,introducing a reactive group into the intermediate polymer at its end asshown in reaction formula (4) below. Note that the polymer had Mn ofabout 110,000 prior to crosslinking. ##STR12##

A humidity sensor was fabricated as in Example 1 and similarly evaluatedfor output and water resistance. The results were equivalent to those ofExample 1.

Example 12

0.82 g (0.0025 mol) of N,N,N',N'-tetraallyl-1,4-diaminobutane, 5.3 g(0.048 mol) of 1,4-diazabicyclo[2.2.2]octane, and 5.7 g (0.05 mol) of1,3-dichloropropane were dissolved in 7.4 g of ethanol and stirred for70 hours at the reflux temperature, effecting quaternization reaction.The resulting polymer was precipitated and purified. Except that thispolymer was used as a conductive component, a humidity sensor wasfabricated as in Example 1 by preparing an aqueous solution of thepolymer and coating it to form a humidity sensitive thin film. Note thatthe polymer had Mn of about 110,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 22 shows plots of output voltageversus relative humidity and FIG. 23 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 22 and 23.

Example 13

A humidity sensor was fabricated as in Example 1 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 20 hours at the reflux temperatureinstead of stirring for 100 hours at 35° C. Note that the polymer had Mnof about 130,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 1. FIG. 24 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 1 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 1 whereby some reactive groups underwent polymerization.

Example 14

A humidity sensor was fabricated as in Example 2 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 25 hours at 80° C. instead ofstirring for 120 hours at 45° C. Note that the polymer had Mn of about90,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 2. FIG. 25 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 2 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 2 whereby some reactive groups underwent polymerization.

Example 15

A humidity sensor was fabricated as in Example 3 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 20 hours at 80° C. instead ofstirring for 120 hours at 45° C. Note that the polymer had Mn of about80,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 3. FIG. 26 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 3 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 3 whereby some reactive groups underwent polymerization.

Example 16

A humidity sensor was fabricated as in Example 5 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 20 hours at 80° C. instead ofstirring for 120 hours at 45° C. Note that the polymer had Mn of about80,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 5. FIG. 27 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 5 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 5 whereby some reactive groups underwent polymerization.

Example 17

A humidity sensor was fabricated as in Example 6 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 20 hours at 80° C. instead ofstirring for 120 hours at 45° C. Note that the polymer had Mn of about80,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 6. FIG. 28 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 6 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 6 whereby some reactive groups underwent polymerization.

Example 18

A humidity sensor was fabricated as in Example 7 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 20 hours at 80° C. instead ofstirring for 120 hours at 45° C. Note that the polymer had Mn of about100,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 7. FIG. 29 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 7 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 7 whereby some reactive groups underwent polymerization.

Example 19

A humidity sensor was fabricated as in Example 9 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 20 hours at 80° C. instead ofstirring for 100 hours at 35° C. Note that the polymer had Mn of about80,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 9. FIG. 30 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 9 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 9 whereby some reactive groups underwent polymerization.

Example 20

A humidity sensor was fabricated as in Example 10 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 20 hours at the reflux temperatureinstead of stirring for 100 hours at 35° C. Note that the polymer had Mnof about 150,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 10. FIG. 31 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 10 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 10 whereby some reactive groups underwent polymerization.

Example 21

A humidity sensor was fabricated as in Example 11 except that inintroducing a reactive group into the intermediate polymer at its end,the reaction solution was stirred for 20 hours at 80° C. instead ofstirring for 100 hours at 35° C. Note that the polymer had Mn of about150,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 11. FIG. 32 shows the results of thewater resistance test. The water resistance of the sensor of thisExample was better than that of Example 11 since the reactive group wasintroduced into the intermediate polymer at a higher temperature than inExample 11 whereby some reactive groups underwent polymerization.

Example 22

In 10.0 g of methanol were dissolved 4.25 g (0.020 mol) of1,3-di(4-pyridyl)propane, 8.13 g (0.047 mol) ofN,N,N',N'-tetramethyl-1,6-diaminohexane, and 7.62 g (0.067 mol) of1,3-dichloropropane. The solution was stirred for 25 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 3.81 g (0.034 mol) of1,3-dichloropropane and 20.0 g of methanol were added. The solution wasstirred for a further 25 hours at the reflux temperature. At the end ofreaction, the reaction solution was cooled, to which 30 g of 2-propanolwas added. The reaction solution was added dropwise to a large volume ofacetone whereupon an intermediate polymer precipitated. The precipitatewas collected by filtration through a glass filter and dried in vacuum.

Then 15.0 g of the intermediate polymer, 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide and 0.2 g of m-dinitrobenzene asa polymerization inhibitor were dissolved in 30.0 g of methanol. Thesolution was stirred at the reflux temperature for 20 hours, introducinga reactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum.

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 130,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 33 shows plots of output voltageversus relative humidity and FIG. 34 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 33 and 34.

Example 23

In 10.0 g of methanol were dissolved 2.52 g (0.022 mol) of1,4-diazabicyclo[2.2.2]octane, 9.03 g (0.052 mol) ofN,N,N',N'-tetramethyl-1,6-diaminohexane, and 8.46 g (0.075 mol) of1,3-dichloropropane. The solution was stirred for 25 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 4.23 g (0.037 mol) of1,3-dichloropropane and 20.0 g of methanol were added. The reactionsolution was stirred for a further 25 hours at the reflux temperature.At the end of reaction, the reaction solution was cooled, to which 30 gof 2-propanol was added. The reaction solution was added dropwise to alarge volume of acetone whereupon an intermediate polymer precipitated.The precipitate was collected by filtration through a glass filter anddried in vacuum.

Then 15.0 g of the intermediate polymer, 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide and 0.2 g of m-dinitrobenzene asa polymerization inhibitor were dissolved in 30.0 g of methanol. Thesolution was stirred at the reflux temperature for 20 hours, introducinga reactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum.

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 110,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 35 shows plots of output voltageversus relative humidity and FIG. 36 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 35 and 36.

Example 24

In 10.0 g of methanol were dissolved 2.51 g (0.022 mol) ofN,N'-dimethylpiperazine, 9.01 g (0.052 mol) ofN,N,N',N'-tetramethyl-1,6-diaminohexane, and 8.44 g (0.075 mol) of1,3-dichloropropane. The solution was stirred for 25 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 4.22 g (0.037 mol) of1,3-dichloropropane and 20.0 g of methanol were added. The reactionsolution was stirred for a further 25 hours at the reflux temperature.At the end of reaction, the reaction solution was cooled, to which 30 gof 2-propanol was added. The reaction solution was added dropwise to alarge volume of acetone whereupon an intermediate polymer precipitated.The precipitate was collected by filtration through a glass filter anddried in vacuum.

Then 15.0 g of the intermediate polymer, 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide and 0.2 g of m-dinitrobenzene asa polymerization inhibitor were dissolved in 30.0 g of methanol. Thesolution was stirred at the reflux temperature for 20 hours, introducinga reactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum.

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 120,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 37 shows plots of output voltageversus relative humidity and FIG. 38 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 37 and 38.

Example 25

In 10.0 g of methanol were dissolved 4.69 g (0.020 mol) ofN,N'-dimethyl-1,3-dipiperidylpropane, 7.90 g (0.046 mol) ofN,N,N',N'-tetramethyl-1,6-diaminohexane, and 7.41 g (0.066 mol) of1,3-dichloropropane. The solution was stirred for 25 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 3.71 g (0.033 mol) of1,3-dichloropropane and 20.0 g of methanol were added. The reactionsolution was stirred for a further 25 hours at the reflux temperature.At the end of reaction, the reaction solution was cooled, to which 30 gof 2-propanol was added. The reaction solution was added dropwise to alarge volume of acetone whereupon an intermediate polymer precipitated.The precipitate was collected by filtration through a glass filter anddried in vacuum.

Then 15.0 g of the intermediate polymer, 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide and 0.2 g of m-dinitrobenzene asa polymerization inhibitor were dissolved in 30.0 g of methanol. Thesolution was stirred at the reflux temperature for 20 hours, introducinga reactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum.

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 90,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 39 shows plots of output voltageversus relative humidity and FIG. 40 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 39 and 40.

Example 26

In 10.0 g of methanol were dissolved 9.29 g (0.083 mol) of1,4-diazabicyclo[2.2.2]octane and 10.71 g (0.069 mol) of1,6-dichlorohexane. The solution was stirred for 15 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 4.65 g (0.041 mol) of1,4-diazabicyclo[2.2.2]octane and 20.0 g of methanol were added. Thereaction solution was stirred for a further 15 hours at the refluxtemperature. At the end of reaction, the reaction solution was cooled,to which 30 g of 2-propanol was added. The reaction solution was addeddropwise to a large volume of acetone whereupon an intermediate polymerprecipitated. The precipitate was collected by filtration through aglass filter and dried in vacuum (yield 15.5 g).

Then 15.0 g of the intermediate polymer and 15.0 g of vinylbenzylchloride (mixture of m- and p-forms) were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 20.3 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 50,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 41 shows plots of output voltageversus relative humidity and FIG. 42 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 41 and 42.

Example 27

In 10.0 g of methanol were dissolved 3.68 g (0.033 mol) of1,4-diazabicyclo[2.2.2]octane, 7.83 g (0.033 mol) of4,4'-trimethylenebis(1-methylpiperidine), and 8.49 g (0.055 mol) of1,6-dichlorohexane. The solution was stirred for 15 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 3.68 g (0.033 mol) of1,4-diazabicyclo[2.2.2]octane and 20.0 g of methanol were added. Thereaction solution was stirred for a further 151 hours at the refluxtemperature. At the end of reaction, the reaction solution was cooled,to which 30 g of 2-propanol was added. The reaction solution was addeddropwise to a large volume of acetone whereupon an intermediate polymerprecipitated. The precipitate was collected by filtration through aglass filter and dried in vacuum (yield 16.2 g).

Then 15.0 g of the intermediate polymer and 15.0 g of vinylbenzylchloride (mixture of m- and p-forms) were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 19.2 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 60,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 43 shows plots of output voltageversus relative humidity and FIG. 44 shows the results of the waterresistance test.

The advantages of the present invention are evident from FIGS. 43 and44.

Example 28

In 10.0 g of methanol were dissolved 9.46 g (0.084 mol) of1,4-diazabicyclo[2.2.2]octane, 8.72 g (0.056 mol) of 1,6-dichlorohexane,and 1.81 g (0.014 mol) of 1,3-dichloro-2-propanol. The solution wasstirred for 15 hours at the reflux temperature, effecting quaternizationreaction. At the end of reaction, the reaction solution was cooled, towhich 4.73 g (0.042 mol) of 1,4-diazabicyclo[2.2.2]octane and 20.0 g ofmethanol were added. The reaction solution was stirred for a further 15hours at the reflux temperature. At the end of reaction, the reactionsolution was cooled, to which 30 g of 2-propanol was added. The reactionsolution was added dropwise to a large volume of acetone whereupon anintermediate polymer precipitated. The precipitate was collected byfiltration through a glass filter and dried in vacuum (yield 15.2 g).

Then 15.0 g of the intermediate polymer and 15.0 g of vinylbenzylchloride (mixture of m- and p-forms) were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 18.2 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 40,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 45 shows plots of output voltageversus relative humidity and FIG. 46 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 45 and 46.

Example 29

In 10.0 g of methanol were dissolved 7.52 g (0.067 mol) of1,4-diazabicyclo[2.2.2]octane and 12.48 g (0.080 mol) of1,6-dichlorohexane. The solution was stirred for 15 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 6.24 g (0.040 mol) of1,6-dichlorohexane and 20.0 g of methanol were added. The reactionsolution was stirred for a further 15 hours at the reflux temperature.At the end of reaction, the reaction solution was cooled, to which 30 gof 2-propanol was added. The reaction solution was added dropwise to alarge volume of acetone whereupon an intermediate polymer precipitated.The precipitate was collected by filtration through a glass filter anddried in vacuum (yield 17.5 g).

Then 15.0 g of the intermediate polymer and 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 18.4 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 50,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 47 shows plots of output voltageversus relative humidity and FIG. 48 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 47 and 48.

Example 30

The intermediate polymer synthesized, separated and purified in Example29, 15.0 g, and 15.0 g of N-(3-dimethylaminopropyl)acrylamide weredissolved in 30.0 g of methanol. The solution was stirred at 25° C. for24 hours, introducing a reactive group into the intermediate polymer atits end. At the end of reaction, 30 g of 2-propanol was added to thereaction solution, which was added dropwise to a large volume of acetonewhereupon the polymer precipitated. The precipitate was collected byfiltration through a glass filter and then dried in vacuum (yield 16.2g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 50,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 29. FIG. 49 shows the results of thewater resistance test. The advantages of the present invention areevident from these results.

Example 31

In 10.0 g of methanol were dissolved 9.46 g (0.084 mol) of1,4-diazabicyclo[2.2.2]octane, 8.72 g (0.056 mol) of 1,6-dichlorohexane,and 1.81 g (0.014 mol) of 1,3-dichloro-2-propanol. The solution wasstirred for 15 hours at the reflux temperature, effecting quaternizationreaction. At the end of reaction, the reaction solution was cooled, towhich 5.42 g (0.042 mol) of 1,3-dichloro-2-propanol and 20.0 g ofmethanol were added. The reaction solution was stirred for a further 15hours at the reflux temperature. At the end of reaction, the reactionsolution was cooled and added dropwise to a large volume of acetonewhereupon an intermediate polymer precipitated. The precipitate wascollected by filtration through a glass filter and dried in vacuum(yield 18.1 g).

Then 15.0 g of the intermediate polymer and 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 15.4

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 40,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 50 shows plots of output voltageversus relative humidity and FIG. 51 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 50 and 51.

Example 32

In 10.0 g of methanol were dissolved 9.38 g (0.082 mol) ofN,N'-dimethylpiperazine and 10.62 g (0.068 mol) of 1,6-dichlorohexane.The solution was stirred for 15 hours at the reflux temperature,effecting quaternization reaction. At the end of reaction, the reactionsolution was cooled, to which 4.69 g (0.041 mol) ofN,N'-dimethylpiperazine and 20.0 g of methanol were added. The reactionsolution was stirred for a further 15 hours at the reflux temperature.At the end of reaction, the reaction solution was cooled and addeddropwise to a large volume of acetone whereupon an intermediate polymerprecipitated. The precipitate was collected by filtration through aglass filter and dried in vacuum (yield 15.1 g).

Then 15.0 g of the intermediate polymer and 15.0 g of vinylbenzylchloride (mixture of m- and p-forms) were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 19.2 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 50,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 52 shows plots of output voltageversus relative humidity and FIG. 53 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 52 and 53.

Example 33

In 10.0 g of methanol were dissolved 4.63 g (0.041 mol) of1,4-diazabicyclo[2.2.2]octane, 4.71 g (0.041 mol) ofN,N'-dimethylpiperazine, and 10.66 g (0.069 mol) of 1,6-dichlorohexane.The solution was stirred for 15 hours at the reflux temperature,effecting quaternization reaction. At the end of reaction, the reactionsolution was cooled, to which 4.63 g (0.041 mol) of1,4-diazabicyclo[2.2.2]octane and 20.0 g of methanol were added. Thereaction solution was stirred for a further 15 hours at the refluxtemperature. At the end of reaction, the reaction solution was cooledand added dropwise to a large volume of acetone whereupon anintermediate polymer precipitated. The precipitate was collected byfiltration through a glass filter and dried in vacuum (yield 17.2 g).

Then 15.0 g of the intermediate polymer and 15.0 g of vinylbenzylchloride (mixture of m- and p-forms) were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 20.2 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 70,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 54 shows plots of output voltageversus relative humidity and FIG. 55 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 54 and 55.

Example 34

In 10.0 g of methanol were dissolved 8.48 g (0.074 mol) ofN,N'-dimethylpiperazine and 3.82 g (0.089 mol) of 1,6-dichlorohexane.The solution was stirred for 15 hours at the reflux temperature,effecting quaternization reaction. At the end of reaction, the reactionsolution was cooled, to which 6.91 g (0.045 mol) of 1,6-dichlorohexaneand 20.0 g of methanol were added. The reaction solution was stirred fora further 15 hours at the reflux temperature. At the end of reaction,the reaction solution was cooled and added dropwise to a large volume ofacetone whereupon an intermediate polymer precipitated. The precipitatewas collected by filtration through a glass filter and dried in vacuum(yield 17.1 g).

Then 15.0 g of the intermediate polymer and 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 17.4 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 70,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 56 shows plots of output voltageversus relative humidity and FIG. 57 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 56 and 57.

Example 35

The intermediate polymer synthesized, separated and purified in Example34, 15.0 g, and 15.0 g of N-(3-dimethylaminopropyl)acrylamide weredissolved in 30.0 g of methanol. The solution was stirred at 25° C. for24 hours, introducing a reactive group into the intermediate polymer atits end. At the end of reaction, 30 g of 2-propanol was added to thereaction solution, which was added dropwise to a large volume of acetonewhereupon the polymer precipitated. The precipitate was collected byfiltration through a glass filter and then dried in vacuum (yield 15.1g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 70,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 34. FIG. 58 shows the results of thewater resistance test. The advantages of the present invention areevident from these results.

Example 36

In 10.0 g of methanol were dissolved 3.75 g (0.033 mol) of1,4-diazabicyclo[2.2.2]octane, 3.82 g (0.033 mol) ofN,N'-dimethylpiperazine, and 12.44 g (0.080 mol) of 1,6-dichlorohexane.The solution was stirred for 15 hours at the reflux temperature,effecting quaternization reaction. At the end of reaction, the reactionsolution was cooled, to which 6.22 g (0.040 mol) of 1,6-dichlorohexaneand 20.0 g of methanol were added. The reaction solution was stirred fora further 15 hours at the reflux temperature. At the end of reaction,the reaction solution was cooled and added dropwise to a large volume ofacetone whereupon an intermediate polymer precipitated. The precipitatewas collected by filtration through a glass filter and dried in vacuum(yield 17.5 g).

Then 15.0 g of the intermediate polymer and 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 18.4 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 50,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 59 shows plots of output voltageversus relative humidity and FIG. 60 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 59 and 60.

Example 37

The intermediate polymer synthesized, separated and purified in Example36, 15.0 g, and 15.0 g of N-(3-dimethylaminopropyl)acrylamide weredissolved in 30.0 g of methanol. The solution was stirred at 25° C. for24 hours, introducing a reactive group into the intermediate polymer atits end. At the end of reaction, 30 g of 2-propanol was added to thereaction solution, which was added dropwise to a large volume of acetonewhereupon the polymer precipitated. The precipitate was collected byfiltration through a glass filter and then dried in vacuum (yield 18.2

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 50,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 36. FIG. 61 shows the results of thewater resistance test. The advantages of the present invention areevident from these results.

Example 38

In 10.0 g of methanol were dissolved 3.74 g (0.033 mol) ofN,N'-dimethylpiperazine, 7.80 g (0.033 mol) of4,4'-trimethylenebis(1-methylpiperidine), and 8.46 g (0.055 mol) of1,6-dichlorohexane. The solution was stirred for 15 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 3.74 g (0.033 mol) ofN,N'-dimethylpiperazine and 20.0 g of methanol were added. The reactionsolution was stirred for a further 15 hours at the reflux temperature.At the end of reaction, the reaction solution was cooled and 30 g of2-propanol was added thereto. The solution was added dropwise to a largevolume of acetone whereupon an intermediate polymer precipitated. Theprecipitate was collected by filtration through a glass filter and driedin vacuum (yield 15.5 g).

Then 15.0 g of the intermediate polymer and 15.0 g of vinylbenzylchloride (mixture of m- and p-forms) were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 12.2 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 60,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 62 shows plots of output voltageversus relative humidity and FIG. 63 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 62 and 63.

Example 39

In 10.0 g of methanol were dissolved 3.15 g (0.028 mol) ofN,N'-dimethylpiperazine, 6.58 g (0.028 mol) of4,4'-trimethylenebis(1-methylpiperidine), and 10.27 g (0.065 mol) of1,6-dichlorohexane. The solution was stirred for 15 hours at the refluxtemperature, effecting quaternization reaction. At the end of reaction,the reaction solution was cooled, to which 5.14 g (0.033 mol) of1,6-dichlorohexane and 20.0 g of methanol were added. The reactionsolution was stirred for a further 15 hours at the reflux temperature.At the end of reaction, the reaction solution was cooled and 30 g of2-propanol was added thereto. The solution was added dropwise to a largevolume of acetone whereupon an intermediate polymer precipitated. Theprecipitate was collected by filtration through a glass filter and driedin vacuum (yield 16.5 g).

Then 15.0 g of the intermediate polymer and 15.0 g ofN-(3-dimethylaminopropyl)methacrylamide were dissolved in 30.0 g ofmethanol. The solution was stirred at 25° C. for 24 hours, introducing areactive group into the intermediate polymer at its end. At the end ofreaction, 30 g of 2-propanol was added to the reaction solution, whichwas added dropwise to a large volume of acetone whereupon the polymerprecipitated. The precipitate was collected by filtration through aglass filter and then dried in vacuum (yield 15.4 g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 50,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. FIG. 64 shows plots of output voltageversus relative humidity and FIG. 65 shows the results of the waterresistance test. The advantages of the present invention are evidentfrom FIGS. 64 and 65.

Example 40

The intermediate polymer synthesized, separated and purified in Example39, 15.0 g, and 15.0 g of N-(3-dimethylaminopropyl)acrylamide weredissolved in 30.0 g of methanol. The solution was stirred at 25° C. for24 hours, introducing a reactive group into the intermediate polymer atits end. At the end of reaction, 30 g of 2-propanol was added to thereaction solution, which was added dropwise to a large volume of acetonewhereupon the polymer precipitated. The precipitate was collected byfiltration through a glass filter and then dried in vacuum (yield 17.9g).

Except that this polymer was used as a conductive component, a humiditysensor was fabricated as in Example 1 by preparing an aqueous solutionof the polymer and coating it to form a humidity sensitive thin film.Note that the polymer had Mn of about 60,000 prior to crosslinking.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 39. FIG. 66 shows the results of thewater resistance test. The advantages of the present invention areevident from these results.

Example 41

Using the same coating solution as in Example 1, a humidity sensitivethin film was formed as in Example 1. The humidity sensitive thin filmwas coated and impregnated with a solution containing 0.25% by weight ofamorphous Teflon (Teflon AF2400, E. I. dupont) in a saturated fluorinecarbide (Florinato FC-43, Sumitomo 3M K.K.) by dipping. Air dryingyielded a water-repellent coating, completing a humidity sensor.

The humidity sensor was evaluated for output and examined by the waterresistance test as in Example 1. The output voltage versus relativehumidity was the same as in Example 1. FIG. 67 shows the results of thewater resistance test. The advantages of the present invention areevident from these results.

Example 42

Using the same coating solution as in Example 2, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 2. FIG. 68 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 43

Using the same coating solution as in Example 3, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 3. FIG. 69 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 44

Using the same coating solution as in Example 4, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 4. FIG. 70 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 45

Using the same coating solution as in Example 5, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 5. FIG. 71 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 46

Using the same coating solution as in Example 6, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 6. FIG. 72 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 47

Using the same coating solution as in Example 7, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 7. FIG. 73 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 48

Using the same coating solution as in Example 8, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 8. FIG. 74 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 49

Using the same coating solution as in Example 9, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 9. FIG. 75 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 50

Using the same coating solution as in Example 10, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 10. FIG. 76 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 51

Using the same coating solution as in Example 11, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 11. FIG. 77 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 52

Using the same coating solution as in Example 12, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 12. FIG. 78 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 53

Using the same coating solution as in Example 13, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 13. FIG. 79 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 54

Using the same coating solution as in Example 14, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 14. FIG. 80 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 55

Using the same coating solution as in Example 15, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 15. FIG. 81 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 56

Using the same coating solution as in Example 16, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 16. FIG. 82 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 57

Using the same coating solution as in Example 17, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 17. FIG. 83 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 58

Using the same coating solution as in Example 18, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 18. FIG. 84 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 59

Using the same coating solution as in Example 19, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 19. FIG. 85 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 60

Using the same coating solution as in Example 20, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 20. FIG. 86 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 61

Using the same coating solution as in Example 21, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 21. FIG. 87 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 62

Using the same coating solution as in Example 22, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 22. FIG. 88 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 63

Using the same coating solution as in Example 23, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 23. FIG. 89 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 64

Using the same coating solution as in Example 24, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 24. FIG. 90 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 65

Using the same coating solution as in Example 25, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 25. FIG. 91 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 66

Using the same coating solution as in Example 26, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 26. FIG. 92 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 67

Using the same coating solution as in Example 27, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 27. FIG. 93 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 68

Using the same coating solution as in Example 28, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 28. FIG. 94 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 69

Using the same coating solution as in Example 29, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 29. FIG. 95 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 70

Using the same coating solution as in Example 30, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 30. FIG. 96 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 71

Using the same coating solution as in Example 31, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 31. FIG. 97 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 72

Using the same coating solution as in Example 32, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 32. FIG. 98 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 73

Using the same coating solution as in Example 33, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 33. FIG. 99 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 74

Using the same coating solution as in Example 34, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 34. FIG. 100 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 75

Using the same coating solution as in Example 35, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 35. FIG. 100 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 76

Using the same coating solution as in Example 36, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 36. FIG. 102 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 77

Using the same coating solution as in Example 37, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 37. FIG. 103 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 78

Using the same coating solution as in Example 38, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 38. FIG. 104 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 79

Using the same coating solution as in Example 39, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 39. FIG. 105 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Example 80

Using the same coating solution as in Example 40, a humidity sensitivethin film was formed as in Example 1. Then as in Example 41, awater-repellent coating was formed on the humidity sensitive thin film,completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. The output voltage versus relative humidity was the same asin Example 40. FIG. 106 shows the results of the water resistance test.The advantages of the present invention are evident from these results.

Humidity sensitive thin films were prepared and humidity sensors werefabricated as in Examples 1-7, 9-11, and 13-40 except that a diaminecompound and a dihalogen compound both other than the above-mentionedones were used in different combinations, the amounts of these compoundsadded were changed in accordance with reaction scheme I (Example 1) andreaction scheme II (Example 11), and a compound having an ethylenicallyunsaturated reactive group was changed. For combinations of diamine anddihalogen compounds analogous to Examples 8 and 12, humidity sensitivethin films were prepared and humidity sensors were fabricated as inExample 1. These humidity sensors were similarly tested for output andwater resistance, finding that results equivalent to those of Examples1-40 were obtained depending on the particular diamine and dihalogencompounds and reaction conditions used.

Comparative Example 1

A humidity sensor was fabricated in accordance with JP-B 7976/1987 andexamined for output as in Example 1. FIG. 107 shows plots of outputvoltage versus relative humidity.

The humidity sensitive material used herein waspoly(2-hydroxy-3-methacryloxypropyltrimethylammonium chloride) of thefollowing formula. A humidity sensitive thin film was formed by coatinga solution of this polymer to an electrode-bearing substrate, applyingan ammonium bichromate solution to the coating, baking the coating,irradiating ultraviolet radiation for 2 or 3 minutes for crosslinking.##STR13##

It is seen from FIG. 107 that this sensor developed hysteresis in aregion of RH 0% to 30%, suggesting inferior output property as comparedwith the inventive humidity sensors.

Comparative Example 2

A humidity sensor was fabricated in accordance with the secondembodiment of JP-B 24465/1990 and examined for output and waterresistance as in Example 1. FIG. 108 shows plots of output voltageversus relative humidity. FIG. 109 shows the results of the waterresistance test.

The humidity sensitive material used herein was a polymer of thefollowing formula which is formed by reacting equimolar amounts ofN,N,N',N'-tetramethyl-1,6-diaminohexane and 1,6-dibromohexane in amixture of acetonitrile and methanol in a volume ratio of 1:1. Ahumidity sensitive thin film was formed by dipping an electrode-bearingsubstrate in a coating solution containing 1 part by weight of thepolymer and 16 parts by weight of polyvinyl pyrrolidone in 383 parts byweight of deionized water. ##STR14##

It is seen from FIG. 108 that humidity is unmeasurable in a region of RH0% to 10%. This is the same tendency as the inventive sensors whereindibromo compounds are used as the dihalogen compound. FIG. 109 showsthat this sensor is least resistant to water. This sensor does notsatisfy both output property and water resistance as do the inventivesensors.

Comparative Example 3

Using the same coating solution as in Comparative Example 2, a humiditysensitive thin film was formed as in Comparative Example 2. Then as inExample 41, a water-repellent coating was formed on the humiditysensitive thin film, completing a humidity sensor.

The humidity sensor was tested for output and water resistance as inExample 1. FIG. 110 shows plots of output voltage versus relativehumidity. FIG. 111 shows the results of the water resistance test. It isseen from FIG. 110 that this sensor has the same output property as inComparative Example 2. It is seen from FIG. 111 that water resistanceremains inferior despite the presence of a water-repellent coating onthe humidity sensitive thin film.

There has been described a humidity sensor which is fully resistant towater so that it ensures stable operation over a long time even in a dewcondensing atmosphere. The sensor is free of hysteresis and able tomeasure humidity over a very wide range. Particularly when the counterion to a quaternary ammonium salt group of the polymer is a chlorideanion, measurement is possible even in a low humidity region of up to RH10%. Then the sensor is able to measure humidity over the entire regionof RH 0% to 100%.

Japanese Patent Application No. 87866/1994 is incorporated herein byreference.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it will be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

We claim:
 1. A humidity sensor comprising an insulating substrate, apair of opposed electrodes disposed on the substrate and defining a gaptherebetween, and a humidity sensitive thin film disposed on thegap,said humidity sensitive thin film containing a cross-linked productof a polymer of the following formula (1): ##STR15## wherein A and Beach are a divalent group, Y₁, Y₂, Y₃, Y₄, Y₅, and Y₆ each are amonovalent group, at least one of Y₁ to Y₆ is a group terminated with anethylenically unsaturated reactive group,optionally at least two of Y₁,Y₂, Y₃, Y₄, Y₅, A, and portions of Y₁, Y₂, Y₃, Y₄, Y₅, and A adjoiningthe nitrogen (N) atom, or at least two of Y₄, Y₅, Y₆, B, and portions ofY₄, Y₅, Y₆, and B adjoining the nitrogen (N) atom, taken together, forma ring with the nitrogen atom, X is a halide ion, and n is a number of 2to 5,000.
 2. The humidity sensor of claim 1 wherein said polymer has thefollowing formula (2) or (3): ##STR16## wherein A and B each are adivalent group, each of R₁, R₂, R₃, and R₄ is an alkyl or alkenyl group,R₁ and R₂, R₁ and A or a portion of A, R₂ and A or a portion of A, R₃and R₄, R₃ and A or a portion of A, R₄ and A or a portion of A, R₁ andR₃, R₁ and R₄, R₂ and R₃, or R₂ and R₄, taken together, optionally forma ring with the nitrogen (N) atom,R₅ and R₆ each are an alkyl or alkenylgroup, L is a divalent group, R is a hydrogen atom or alkyl group, X⁻ isa halide ion, and letter n is a number of 2 to 5,000.
 3. The humiditysensor of claim 1 wherein the halide ion represented by X⁻ is a chlorideion.
 4. The humidity sensor of claim 1 wherein the divalent grouprepresented by A is an alkylene, alkenylene or arylene group or amixture thereof.
 5. The humidity sensor of claim 1 wherein the divalentgroup represented by B is alkylene, alkenylene or arylene groupoptionally containing at least one of and oxy group (--O--) or acarbonyl group (--CO--) or a mixture thereof.
 6. The humidity sensor ofclaim 1 wherein said polymer is obtained by reacting a diamine compoundwith a dihalogen compound to form an intermediate polymer andintroducing an ethylenically unsaturated reactive group into theintermediate polymer at each end.
 7. The humidity sensor of claim 1wherein said crosslinked product is obtained by exposing said polymer toradiation.
 8. The humidity sensor of claim 1 which further comprises awater-repellent coating on said humidity sensitive thin film.
 9. Thehumidity sensor of claim 1 prepared by the steps comprising:coating anaqueous solution of the polymer as set forth in claim 1, and exposingthe polymer to ultraviolet radiation for crosslinking, thereby forming ahumidity sensitive thin film.